1. Field of the Invention
This invention relates generally to a connector assembly for interconnecting optical fibers, and more particularly to fiber optic connectors having elastomeric seals over the mating components to enclose and protect the optical interface from contamination during repeated mating and de-mating in a contaminated air or an underwater environment.
2. Description of the Prior Art
Various types of connectors are known that provide low loss coupling of optical fibers. They typically comprise a plug and receptacle or a plug-adapter-plug arrangement wherein precision mating coaxial components of the connector assembly containing pre-aligned fibers with optically prepared ends are brought together in the connecting process to achieve alignment and abutment of the mating fibers to within micron tolerances. These mating surfaces are usually covered by protective caps which are removed prior to engagement. The connecting of fibers can also be achieved within alignment guides, such as that described in U.S. Pat. No. 4,225,214, wherein abutting fibers are coaxially aligned by their own precision outside diameters in a common "V" groove or other similar means and thereby reduce the need for precision alignment and engagement of the supporting mechanical elements in the connector halves. However, the fiber ends are susceptible to contamination prior to engagement and a method for enclosing and protecting the fibers for this type of connecting device is described in U.S. Pat. No. 4,411,491 entitled "Connector Assembly with Elastomeric Sealing Membranes Having Slits." The plug component has an optical fiber contained therein and an elastomeric sealing membrane with slit covering the mating end and sealing same. The receptacle component has an optical fiber receiving means therein and also an elastomeric sealing membrane with slit covering the mating end and sealing same. The connector further includes displacement means which open and close the slits to permit passage of the fiber during engagement and disengagement of the components. However, none of the engagement techniques described therein prevent the fiber from being exposed to the environment during the actual mating sequence and thus the aforementioned disclosure does not provide a method for engagement of optical fibers within a contaminated environment. Other prior art fiber optic connectors use lenses to expand the optical path at the connecting interface to reduce the effect of small particles or suspended matter between the connecting optical elements. Critical mechanical alignment and protection of the mating optical elements from environmental effects is still a requirement, however.
While such alignment and mating techniques provide acceptable connector loss for many optical fibers under limited environmental conditions, none provide adequate means for achieving repeatable low-loss coupling of single-mode fiber in a contaminated high-pressure environment such as found near the ocean sea floor.
It is an object of this invention to provide a fiber optic connector suitable for deep ocean use that seals and protects the mating ends of abutting optical fibers in each connector half prior to mating and has the means for maintaining this sealed condition during repeated engagement and disengagement without exposing the fiber or its optical interface to the surrounding environment.
Another object of this invention is to provide complete interchangeability of plugs and receptacles while accomplishing the mating/de-mating of the connector halves by a simple push-pull operation without regard to rotational orientation. Furthermore, means are provided for automatically locking the connecting components in the mated position to prevent axial, angular, transverse or rotational movement at the optical interface.
A third object of this invention is to provide a fiber optic connector having a predetermined length of optical fiber as a service loop within the connector to facilitate multiple terminations to the optical fiber without the need to rework the termination to the cable itself and re-test for proper mechanical strength, strain relief, water blockage and optical performance under a high pressure environment.